A wide variety of computerized wagering game machines are now available to casino operators and players. Computerized wagering game machines range from slot machines to games that are traditionally played live, such as poker, blackjack, roulette, etc. These computerized wagering game machines provide many benefits to game owners and players, including increased reliability over mechanical machines, greater game variety, improved sound and animation, and lower overall management cost.
Typically, when wagering game machines start-up, they take measures for ensuring that their hardware and software components have not been modified or tampered-with. Thus, wagering game machines typically include software for verifying digital signatures of the machine's other software. One drawback of using one software component to authenticate another is that the software authentication component itself is vulnerable to attack. For example, software authentication components may be attacked and modified when they are loaded into main memory from a storage medium (e.g., a hard disk drive, ROM, etc.). If a wagering game machine's software authentication components are compromised, the entire system cannot be trusted.
Some wagering game machines authenticate every software component on the machine before executing any single component. After every component is authenticated, the machine may begin executing software components. However, before executing each component, the machine may authenticate the component yet again to confirm that it has not been modified. Such an authentication scheme delays the initialization process, leaving players waiting for machines to “come on-line.” Moreover, such an authentication scheme would not detect whether software components have been modified while they execute.